Simplify the following expression: $4\sqrt{325}$.
First, try to factor a perfect square out of the radical. $= 4\sqrt{325}$ $= 4\sqrt{25 \cdot 13}$ Separate the radical and simplify. $= 4\sqrt{25} \cdot \sqrt{13}$ $= 4 \cdot 5 \cdot \sqrt{13}$ $= 20\sqrt{13}$